A smell of ammonia
AdBlue ammonia smell — a sharp ammonia smell around a diesel means AdBlue is escaping somewhere it should not, or the system is over-dosing. It is not normal and it does not clear itself. Call 01295 380724.
Is the smell strongest at the exhaust, under the car, or in the cabin?
Call 01295 380724 From just £89 call-out fee
AdBlue ammonia smell — what you can observe
| What you can observe | Verdict | What it means |
|---|---|---|
| Strongest at the tailpipe | Likely recoverable | Over-dosing or ammonia slip past the catalyst. It needs live data, not a guess. AdBlue system fault |
| Strongest under the car, with white deposits | Likely recoverable | A leak in the tank or lines, crystallising as it dries. AdBlue crystallisation |
| In the cabin, after a spill in the boot or footwell | Recoverable | Spilled fluid. Dilute with water and ventilate. AdBlue spilled on paintwork |
| Strongest at the filler after topping up | Recoverable | Residue in the neck. Rinse it with water. Overfilled AdBlue tank |
£89 is the call-out. An AdBlue tank drain and flush is quoted on the phone before a technician travels. If the SCR system needs component replacement — dosing injector, pump, tank or catalyst — that is separate, and you will be told before any work starts. If this is a job we cannot fix at the roadside, we will tell you that on the phone rather than after we arrive.
Why symptom first beats diagnosis first
Most drivers arrive at an AdBlue problem through the dashboard, not through a known mistake. A warning lamp, a countdown, a loss of power or a white crust under the car are observations. The diagnosis behind them ranges from a bottle of fluid to a catalyst, and the wrong starting assumption is what gets parts replaced unnecessarily — NOx sensors most of all.
Each branch above ends in a severity verdict rather than a sales line, because a verdict is what you actually need before deciding whether to drive the vehicle, park it, or call someone. From just £89 call-out fee, and you will be told on the phone if this is not a job that can be finished at the roadside.
Before you call
- Write down the exact wording on the dashboard, not just which lamp is lit.
- Note whether the engine has been started since the problem appeared.
- If you added fluid, find the container and read what it claims about ISO 22241.
- Photograph any white crystalline deposit and where it is.
- Call 01295 380724 with those four answers ready.
Common questions
Strongest at the tailpipe?
Over-dosing or ammonia slip past the catalyst. It needs live data, not a guess.
Strongest under the car, with white deposits?
A leak in the tank or lines, crystallising as it dries.
In the cabin, after a spill in the boot or footwell?
Spilled fluid. Dilute with water and ventilate.
Strongest at the filler after topping up?
Residue in the neck. Rinse it with water.
Other symptoms
Explained
What customers say
4.8 out of 5 from 2,190 Trustpilot reviews. What reviewers mention most is that the technician stayed calm and professional with a driver who was embarrassed and stressed, and that somebody arrived when they said they would.
The most common criticism is price. People do not expect a wrong-fluid job to cost what it costs, and that is a fair complaint to publish rather than bury. The answer is the From just £89 call-out fee, a quote given on the phone before a technician travels, and being told when a job cannot be done at the roadside rather than after somebody has arrived and charged for the visit.
Who you are dealing with
AdBlue in Fuel is a service by Forecourt Assist. Forecourt Assist is a trading name of Fuel Fixer Ltd, company no 08520551, registered at Fairway House, Portland Road, East Grinstead, RH19 4ET, a company of Fuel Fixer International. Fuel Fixer International is owned by Stockbridge Capital Holdings.
Reference: DVSA — roadworthiness guidance.
Across the Fuel Fixer network
AdBlue in Fuel is a service by Forecourt Assist, a brand of Fuel Fixer International, owned by Stockbridge Capital Holdings. The full group directory is at forecourtassist.co.uk/network.